Phototherapy is the therapeutic use of light that has been recognized as an effective method of treating wounds and reducing pain in humans. External phototherapy has been effective in treating various medical conditions, such as, but not limited to, bulimia nervosa, herpes, psoriasis, seasonal affective disorder, sleep disorders, acne, skin cancer, hyperbilirubinemia in infants, and other conditions. Phototherapy is typically administered to a patient using a light source consisting of either a bank of lights, referred to as a light bank, or a fiber optic light source. Some of the first phototherapy light sources included light banks positioned over incubators or open bassinets, or under hoods or transparent supports. Typically, the light sources used in phototherapy consist of fluorescent tubes, metal halide lamps, or light-emitting diodes (LEDs).
While light sources having light banks are still being used, such devices are not without their disadvantages. For instance, phototherapy devices using light banks require that patients wear eye protection that is often uncomfortable. These devices also require that patients remain relative stationary while receiving treatment. Furthermore, these devices are typically large and immobile, which thus, require patients to visit the locations of the light sources each time a dosage is needed. Light sources using light banks are disadvantageous for at least these reasons.
Fiber optic light sources were developed as a substitute for phototherapy devices containing light banks but have not eliminated all of the drawbacks associated with these devices. For instance, while the fiber optic lights are more mobile than light bank devices, the fiber optic lights typically deliver lower overall amounts of light than the light banks. Additionally, fiber optic lights are often used in conjunction with fiber optic mats having specific geometries. Often times, the geometries of the fiber optic mats are compromised when forces are placed on the fiber optic mats in order to place the fiber optic mats in contact with patients' skin surfaces. This undesirably results in greater light intensity being concentrated near the light source than at other portions of the fiber optic mat.
LEDs are typically used as light sources for phototherapy. For instance, U.S. Pat. Nos. 6,290,713 and 6,096,066 describe flexible mats having a plurality of LEDs positioned in arrays that are coupled to a plurality of conductive traces for emitting light. The LEDs are point sources that do not emit light over a broad area, but rather over a narrow area. Light produced by the LEDs is diffused and made more uniform by placing diffusers in the mats near the LEDs. Without the diffusers, the arrays of LEDs are simply collections of point sources. Because diffusers are used, the LEDs cannot be placed in contact with a surface. Instead, the thickness of the diffuser limits the proximity with which the LEDs may be positioned proximate to a surface. Thus, the amount of light that an LED emits is not the same amount of light that reaches the surface because a portion of the light produced by the LED is lost when the LED is not placed in contact with a surface.
LEDs produce a single wavelength of light. If more than one wavelength of light is required, more than one type of LED must be used. In order to operate the LEDs, the mats contain numerous conductors to provide power to each LED individually. These conductors significantly add to the overall weight and complexity of the mats.
The mats are made even more complex with the addition of channels for dissipating heat. Use of the plurality of LEDs in such close proximity to each other produces high amounts of heat that can pose potentially dangerous conditions. This heat is typically vented from the devices using channels between the LEDs. While the channels do allow a portion of the heat produced by the LEDs to be vented from the mat, not all of the heat generated is removed.
Thus, a need exists for a phototherapy device that delivers light in a more efficient manner while retaining the advantages of a flexible mat.